Bridge.



UNITED TATES ATENT DAVID E. FISHER, OF KENTON, OHIO.

BRIDGE.

SPEGIFICATION forming part of Letters Patent No. 665,317, dated January1, 1901 Application filed April 12,1900. Serial No. 12.5722 (No model.)

T0 all whom it muy concern:

Be it known that I, DAVID E. FISHER, a citizen of the United States,residing at Kenton, in the county of Hardin and State of Ohio, haveinvented certain new and useful Improvements in Bridges, of which thefollowing is a full, clear, and exact specification.-

My invention consists in certain novel features of the construction of abridge of the type known as suspension-bridges.

In the annexed drawings, which fully illustrate my iuvention, Figure 1is a side elevation of a bridge embodying the features of my presentinvention, and Fig. 2 is a similar view showing a slight modification.

In carrying out my invention I erect piers of masonry or other solidconstruction on the sides of the stream or gorge to be bridged, and uponthese piers I anchor the beams or girders A, as clearly shown. Pivotallysecured to the inner ends of these beams or girders are the posts B, andextending between the beams across the space between the piers are thecables C. The floor of the bridge also extends between the ends of thesebeams A and is supported by the usual joists and chords. Rising from thelower chords, which support the floor at regular iutervals, are theposts D, on which are the pulleys E. The upper ends of these posts arepivotally attached to the upper chord F, which has its ends pivotallyconnected to the upper ends of the posts B. Fnlcrumed on the pivotalconnections of the upper chord F and the posts B are the short leversGr, to the lower ends of which are secured the ends of the cable H,passing underthe pulleys E. The upper ends of the levers G are pivotedto the upper ends of the braces I, extendin'g to the outer ends of thebeams A and anohored.

In the normal position of the parts the locking-levers G have theirlower ends projecting away from the ends of the bridge. When a load isplaced on the bridge, the strain is transmitted directly to the cable Hand exerts an inward pull on the said levers, which tends to swing theirlower ends inward. This movement of course causes an outward movement ofthe upper ends of the lovers, which is resisted by the braces I, so thatthe en:

tire strain put on the bridge is transmitted to and borne by the piers.Should an extraordinary strain be placed on the bridge, thelocking-levers might be brought beyond the vertical position, in whichevent they would tend to lift the posts to which they are fulcrumed; butthis tendency would be positively resisted by the strut-braces betweenthe several posts along the sides of the spau.

My bridge is intended more especially for large streams, but itsprinciple may be utilized in a bridge of any size.

The bridge commends itself by reason of its economical construction andthe rapidity With which it can be built.

It may sometimes be desirable to have the beams A, which are thefoundation of the bridge-approaches, inclined upward,as shown in Fig. 2.In this form of the bridge the lock ing-levers will be arranged withtheir upper ends projeoting from the ends of the bridge. Under thestrain of a load passing over this bridge the approaches will tend toassume a lower position, thereby drawing downward ou the lockirigleversand the braces, as will be readily understood. The braces, beinganchored, will resist this downward movement, and consequently thelevers will swing outward at their lower ends and draw upon the cable,so as to increase the tension of the same and impart additional rigidityto the structure. Should it be necessary to have one approach elevatedmore than the other, this arrangement of the levers (shown in Fig. 2)will be followed.

Single bolts are used throughout the structure, so that the severalconnections will be true pivotal connections and the necessary movementsmay readily occur. It will be readily understood that the resistanceoffered by the bridge is governed by the weight of the load passing overthe span and that the heavier the load the more rigid will the bridgebe. The cables are provided with tu rnbuckles, so as to be readily adjusted to an initial tension. The lower cables serve not only as asupport for the floor, but also serve as a tie between the end beams orgirders to prevent spreading of the lower portion of the bridge.

The weight or load is supported by the cable, so that the partscomposing the top of the bridge may be light without affecting therigidity of the structure. As the length of the bridge increases and theweight becomes of the braces, and a cable secured to and extendingbetween the ends of the levers.

2. The combination with the main structure, and the end braccs, of acable extending longitudinally of the main structure, and locking-leversfulcrumed on the main structure, pivoted to the end braces and acting onthe cable.

3. In a bridge, the combination of the anchored end beams and braces,posts rising from the inner ends of the beams, locking-levers fulcrumed011 the upper ends of the said posts and having their upper ends piv0tedto the upper ends of the braces, and cables extending between the endsof the looking-levers and secured to the lower ends of the same.

4. The combination of the end heams and braces, tie-cables and a floorconnecting the end beams, posts rising from the end beams and from thesides of the floor-span, the intermediate posts, pulleys on the posts,locking-levers fulcrumed on the upper ends of the end posts and pivotedto the end braces, and a cable secured to and extending between the endsof the locking-levers and passing under the pulleys on the posts.

In testimony whereof I have signed this specification in the presence oftwo witnesses.

DAVID E. FISHER.

Witnesses:

EMMA BEEM, W. W. DURBIN.

